This invention relates to pulse detonation systems, and more particularly, to a method for passive valving of pulse detonation combustors.
With the recent development and interest in pulse detonation combustors (PDCs) and engines (PDEs), various efforts have been underway to develop PDCs for use in practical applications, such as combustors for aircraft engines. These efforts have included trying to maximize operating efficiency and duty cycle frequency for a given geometry of the pulse detonation combustor. It is noted that for the purposes of this application, pulse detonation combustor is to include all manner of pulse detonation devices, and is not to be limited to those pulse detonation devices used as combustors.
During the operation of PDCs a mixture of fuel and oxidizer (typically air) is detonated, to generate a high pressure shock wave. The high pressure gases generated by the detonation wave provide thrust, power or work energy, depending on the application of the PDC. Because the overall operation and construction of PDCs is known, a detailed discussion will not be provided herein.
The fuel and oxidizer amounts directed to the detonation chamber of a PDC are typically controlled by mechanical valves, which open and close at a frequency to operate the PDC at a certain fixed duty cycle, or frequency. Thus, the operational frequency of the PDC overall, is typically limited by the operational frequencies of the fuel and/or oxidizer valves. Thus, it is possible that although the geometry and configuration of the PDC will allow for a higher operational frequency, the frequency is limited by the valves. This prevents the PDC from operating at its fullest potential.
Additionally, mechanical valves in such an environment (i.e. high frequency, high temperature and high pressure) tend to have relatively limited operational lives, as well as high frequency maintenance requirements.
Additional efforts have been made to valve only the fuel flow, while the oxidizer flow remains constant. However, again with these types of systems the operational frequency of the PDC is limited by the operational frequency of the fuel flow valves, and in such systems the duty cycle of the PDC geometry is not optimized. Moreover, in such systems, varying the frequency of operation of the PDC (to increase or decrease thrust, power, etc.) is difficult to control efficiently.
Therefore, there is a need to control the operation of PDCs such that the duty cycle of a PDC is optimized, and the control of the fuel and oxidizer flow is simplified.